SEGA and Characters with each letter, each having some involvement with SEGA.
Characters from S to A
S Purple Heart: Neptune from Hyperdimension Neptunia, Neptune is a character based on the never rleased SEGA Neptune, also SEGA were part of creating the Game.
E Hatsune Miku: Project Diva. SEGA have been involved with Hatsune Miku's success, releasing all of her games, and even helping with her live concerts.
G Everyone's favourite Jester Nights, I love Nights and so glad Nights gets into Sonic and All-Star Racing Transformed.
A Of course Sonic the Hedgehog.